The hip joint is a ball-and-socket joint that connects the pelvis and the thigh bones. The hip socket is called the acetabulum and actually forms a deep cup that surrounds the ball of the upper thigh bone or femoral head. The surface of the femoral head and the inside of the acetabulum are covered with a smooth shiny cartilage that cushions, protects and at the same time allows near frictionless movement. Cartilage, which contains no nerve endings or blood supply, receives nutrients from a moisturising lubricant (synovial fluid) produced by the synovial lining surrounding the hip joint. If damaged, the cartilage is not capable of repairing itself. Strong fibres (ligaments) connect the bones of the hip joint and provide necessary stability to the joint and elasticity for its movement. Muscles and tendons also play an important role in keeping the hip joint stable and mobile.

Various Surgical interventions are available depending on the severity of patient's condition and the doctor's judgement. These include

• Femoral Hemiarthroplasty: (Replacement of half a hip).
• Total Hip Replacement (THR)
  • Cemented prosthesis
  • Un-cemented prosthesis
  • Hybrid Total Hip Replacement

After the surgery, once the artificial hip joint has healed, the patient normally benefits from it. The benefits of THR are:

• Reduced joint pain
• Increased movement mobility and stability
• Correction of deformity
• Increased leg strength
• Improved quality of life due to the ability to return to normal activities and pastimes

There are two major types of Total Hip Replacements: a cemented prosthesis and an uncemented prosthesis. Both are widely used.

The surgeon makes the choice based on the patient's age and lifestyle. Each prosthesis is made up of two parts:

• The acetabular component is made of high-density polyethylene. At times it has a metal shell backing. The acetabular component is placed inside the socket.
• The femoral component is made of metal. The femoral head that attaches to the stem may be a separate part. It is made either of metal or ceramic. The femoral stem extends into a canal in the thigh bone.
• When the acetabular component is uncemented and femoral component is cemented, it is called Hybrid Total Hip Replacement.

Today, almost one million people in the developed world undergo total hip replacement surgery every year as a means of diminishing pain and restoring mobility.

Femoral Hemiarthroplasty is done instead of a Total Hip Replacement, when the socket cartilage is normal. The socket is not replaced. The femur component is similar to that of a total hip replacement, but its ball is large and fills the normal socket, bearing directly against the cartilage. Though this is a lesser procedure, it lasts for less time than a Total Hip Replacement.

This is the most modern concept in hip joint replacement wherein only the worn out surfaces of hip joint are replaced with metal capping. It doesn't require removing pieces of the bone from the thigh bone. It is a long lasting joint that permits complete range of movement including squatting and sitting across legged on the floor. The surgery is particularly suited for young patients.

The surface replacement hip technique promises a life as near to normal as possible, with permission to squat, sit cross-legged and indulge in normal as well as sports activities. However this technique can only be employed in certain specific conditions that can be judged by X-rays of the affected hip. The Proxima Hip (a new concept launched for the first time in Asia by Max Institute of Othropaedics and Joint Replacement) counters these limitations as it can be applied in many extended conditions that preclude surface replacement. It is less invasive, does not breach the core of the thigh bone (thus reducing blood loss), is easily changeable to the full hip (if required in future), and at the same time affords all the advantages of the hip resurfacing. It is undoubtedly the hip of the future, especially in young patients who are not suitable for the traditional hip resurfacing.

• Patients must give a detailed account of their medical history to the Surgeon as it may have a bearing on their operation and it's result.
• A detailed medical check is done prior to surgery, to make the surgery safe.
• Certain medicines that one may be taking, particularly blood thinners may have to be stopped or some medicines may be added.
• The patient needs blood transfusion during surgery depending upon the pre-operative haemoglobin levels. Some patients prefer to donate their own blood a few days before the operation, which is transfused back to them on the day of the operation.
• The patient is admitted to the hospital two days before the surgery and advised not to eat or drink anything after midnight on the day of the surgery.
• An injection of blood thinning agent (anti-coagulant) is administered, the evening after the operation, (Deep Vein Thrombosis) to minimise chances of blood clotting in the legs.
• Usually antibiotics are started on the morning of the operation. In patients with greater risk of infection, antibiotics may be started a night before.
• In order to receive medications and blood transfusions during surgery, an intravenous (IV) line will be started. The Anaesthesiologist discusses the type of anaesthetic to be used, before surgery.
• Most people are operated upon under epidural/spinal anaesthesia where their legs are numbed and a fine tube is put in the back through which anaesthetic agent keeps dripping in. This also controls pain in post-operative period.

After the surgery the patient is shifted to the post-operative observation room (HDU). A bandage is tied over the hip with a drain tube coming out of the bandage. This removes any blood collected in the hip joint and minimises the chances of infection. The legs of the patient are kept apart by a pillow in between them.

An intravenous line is used for transfusing blood or fluids into the patient's arm. This is later used to administer antibiotics, over the next few days and transfuse blood. In some instances a urinary catheter may be used to help elderly patients or those who have urinary difficulty.

Some leads are attached to the body to continuously monitor the ECG, blood pressure, pulse rate, breathing rate, etc. The patients remain in the observation room for a night and are shifted to their own room, once the anaesthetists are satisfied with the recovery.

Blood transfusion is usually performed in the observation room (HDU).

• Patients are encouraged to start in-bed exercises within 24 hours of the operation.
• After 24-48 hours, drain from the hip joint is removed and the dressing is reduced in size. Patients are made to sit on bedside with legs supported.
• 2-3 days after the operation, patients with the cemented hip are encouraged to stand and walk using a walker and a day or two later, they are able to visit the toilet, with assistance, using a high seat.
• Stitches are removed 2 weeks after the operation.
• 3 weeks after the operation, patients are encouraged to walk with a walking stick.
• 4-6 weeks after the surgery, patients are trained to start climbing stairs.
• In case of Hybrid or Uncemented Hip Replacement, the patient are usually advised non-weight bearing exercises, 4-6 weeks after the operation.
• The patients are discharged from the hospital one week after the surgery with instructions regarding medicines and physiotherapy.
• 12 weeks post operative, one can usually begin driving vehicles, with due precautions.

• Always use the walker, crutches or cane as advised.
• Walk. It is the most vital physical therapy. Gradually increase the distance.
• Do not sleep sideways until instructed by physician.
• Do not cross the legs at the knees or ankles.
• Do not bend the hip beyond a 90º angle. Low chairs and Indian style toilet, to be avoided.
• Do not pivot or twist on the operated leg.
• Do not bend over to pick up anything from the floor.
• If in doubt about any activity, consult your Surgeon before performing it.

Patients are seen six weeks, three months and twelve months after their surgery. It is requested that the surgeon be visited once a year after the first year, even if there is no problem.

Any infection particularly of urine, skin and dental must be promptly treated with proper antibiotics because infection can spread from one area of the body to another through the blood stream. Every effort must be made to prevent infection in the artificial joint.

Total Hip Replacement is one of the most successful operation for severe Arthritis and to increase the chances of success, the following is advised:

• Choose a surgeon who is a specialist in Joint Replacement Surgery and does them regularly.
• Choose a well-equipped hospital having an operation theatre and facilities appropriate for Joint Replacement surgery
• Discuss with the Surgeon and ensure that good quality implants are used
• Follow the instructions given by your Surgeon

The usual life span of a successful Total Hip Replacement is about 15 years. It may however vary under individual circumstances. A revision join replacement is required then Understanding the Risks.

Problems and aspirations of each individual patient differ and these must be discussed with the Surgeon at length before the patient accepts the Total Hip Replacement operation. Patient must know all, that can go wrong and what can be done to save the situation.

One must realise that one can not squat on the ground after conventional hip joint replacement. This is only for the purpose of information and can not be substituted for medical advice. In case of a query, discuss it with your doctor.

The knee is the largest joint in the body. It is commonly referred to as a 'hinge' joint because it allows the knee to flex and extend (bend and straighten like a door hinge).

Each bone end is covered with a layer of smooth shiny cartilage that cushions and protects while allowing near frictionless movement. In addition, there is a special washer like cartilage between the joint surface of the thigh and leg bones called Meniscus. Cartilage, which contains no nerve endings or blood supply, receives nutrients from the fluid contained within the joint. Surrounding the knee structures is the synovial lining, which produces this moisturising lubricant. If damaged, the cartilage is not capable of repairing itself.

Strong fibres, called ligaments, link the bones of the knee joint and hold them in place, adding stability and elasticity for movement. Muscles and tendons also play an important role in keeping the knee joint stable and mobile.

Depending on the severity of patient's condition and the doctor's judgement various surgical interventions are available . These include:

• Arthroscopic debridement: A telescope is inserted into the knee and products of wear and tear are removed.
• High Tibial Osteotomy: The shin bone (tibia) is cut at the upper end and realigned to distribute the load in a knee. This is possible only in arthritic knees.
• Total Knee Replacement
• Unicondylar Knee Replacement

Total knee replacement or 'Arthroplasty' is relining of the joint (bone end surfaces) with artificial parts called Prostheses. This has a new design called High Flexion Knees permitting near complete range of movement. There are three components used in the artificial knee. The Femoral (thigh) component is made of metal and covers the end of the thigh bone.

The Tibial (shin bone) component, made of metal and UHMWPE (medical-grade plastic), covers the top end of the Tibia. The metal usually Titanium in fixed bearing knees and cobalt chrome in mobile bearing knees. Two varieties of knee design form the base of this component. The polyethylene is attached to the top of the metal to serve as a cushion and form a smooth gliding surface between the metal of the femoral and tibial components.

These components are usually cemented to their respective bones, though some uncemented models are also available.

The third component, the patella or knee cap, is made up of polyethylene. The surgeon decides at the time of operation if it should be replaced in a particular situation or not.

Patients with severe arthritis of both knees can be offered replacements of both knees together after a thorough medical evaluation. Joint replacement is also being done using computer assistance which improves implant alignment and surgical precision.

Hi-Flex Knees : A new design called high flexion knees are now being commonly used. These allow patients, near-complete range of movement at the knee. The patients can comfortably sit cross-legged on the bed. It is suitable for patients with slim legs.

In some patients only one half of the knee joint is worn out. In these situations only one side of the knee is replaced. This is termed as Unicondylar Knee Replacement. It can be done in specific conditions, which only the surgeon can judge and advice.

Unicondylar Knee Replacement is comparatively economical and since the operation is less extensive, the post-operative recovery is faster.

• Patients must give a detailed account of their medical history to the surgeon as it may have a bearing on their operation and it's result.
• A detailed medical check up is done prior to surgery, to make the surgery safe.
• Certain medicines that one may be taking, particularly blood thinners might have to be stopped or some medicines may be added.
• The patient needs blood transfusion during surgery depending upon the pre-operative haemoglobin levels. Some patients prefer to donate their own blood a few days before the operation, which is transfused back to them on the day of the operation.
• The patient is admitted to the hospital two days before the surgery and advised not to eat or drink anything after midnight on the day of surgery.
• An injection of blood thinning agent (anti-coagulant) is administered, evening after the operation, to minimise chances of blood clotting in the legs.
• Usually antibiotics are started on the morning of the operation. In patients with greater risk of infection, antibiotics may be started a night before.
• In order to receive medications and blood transfusions during surgery, an intravenous (IV) line will be started. The Anaesthesiologist discusses the type of anaesthetic to be used, before surgery.
• Most people are operated upon under epidural or spinal anaesthesia where their legs are numbed and a fine tube is put in the back through which anaesthetic agent keeps dripping in. This also controls pain in post-operative period.

After the surgery the patient is shifted to the post-operative observation room (HDU). A bandage is tied over the knee with a drain tube coming out of the bandage. This removes any blood collected in the knee and minimises the chances of infection.

An intravenous line is used for transfusing blood or fluids into the patient's arm. This is later used to administer antibiotics over the next few days and transfuse blood. In some instances a urinary catheter may be used to help elderly patients or those who have urinary difficulty.

Some leads are attached to the body to continuously monitor the ECG, blood pressure, pulse rate, breathing rate, etc. The patients remain in the observation room for a night. Once the anaesthetists are satisfied, patients are shifted to their respective rooms, the next day. Today, more than 50,00,000 people in the developed world undergo Total Knee Replacement surgery every year. This has led to diminished pain and stiffness and helped in restoring mobility.

• Patients are encouraged to start in-bed exercises within 24 hours of the operation.
• After 24-48 hours, drain from the knee joint is removed and the dressing is reduced in size. Patients are made to sit on bedside with legs supported.
• 2-3 days after the operation, patients are encouraged to stand and walk using a walker and a day or two later, they are able to visit the toilet, with assistance, using a high seat.
• Stitches are removed 2 weeks after the operation.
• 3 weeks after the operation, patients are encouraged to walk with a walking stick.
• 4-6 weeks after the surgery, patients are trained to start climbing stairs.
• The patients are discharged from the hospital 5 days after the surgery with instructions regarding medicines and physiotherapy.
• 12 weeks post operative, one can usually begin driving vehicles, with due precautions.
• One is advised not to squat or sit cross-legged after the operation, particularly on the floor.
• The post operation schedule gets slightly extended in case of surgery being performed on both the knees.

One may be seen six weeks, three months and twelve months after the surgery. It is requested that one sees the surgeon once a year after the first year, even if there is no problem.

Any infection, particularly that of urine, skin and dental must be promptly treated with proper antibiotics because infection can spread from one area of the body to another through the blood stream. Every effort must be made to prevent infection in the artificial joint.

Total Knee Replacement is the most successful operation, for severe Arthritis and to increase one's chances of success, the following has to be ensured.

• Choose a Surgeon who is a specialist in Joint Replacement surgery and does them regularly.
• Choose a well-equipped hospital having an operation theatre and facilities appropriate for Joint Replacement surgery.
• Discuss with the Surgeon and ensure that good quality implants are used.
• Follow the instructions given by your Surgeon.

The usual life span of a successful Total Knee Replacement is about 15 years. It may however vary under individual circumstances.

Problems and aspirations of each individual patient differ and these must be discussed with the Surgeon at length before the patient accepts the Total Knee Replacement operation. Patient must know all, that can go wrong and what can be done to save the situation.

One must realise that one cannot squat on the ground after knee joint replacement.

This is only for the purpose of information and can not be substituted for medical advice.

In case of a query, discuss it with your doctor.